EP2532078A1 - Device for guiding air in a suction system for a rotary electrical machine - Google Patents

Abstract

The invention relates to a guidance device (10) of a suction system, said suction system being designed to suck up the dust generated by a brush (1) rubbing against a rotary element (2) in a rotary electrical machine, the guidance device (10) being designed in such a way as to concentrate a stream of air (F) generated by the suction system, near the end of the brush that is in contact with the rotary element (2). The guidance device defines at least one suction chamber (12) shaped so that it opens towards the rotary element, said at least one chamber having walls extending in a longitudinal direction so that said assembly is shaped so as to surround part of a brush near said end. The invention also relates to a suction system comprising such a guidance device.

Description

 AIR GUIDING DEVICE IN AN EXHAUST SYSTEM FOR A ROTATING ELECTRIC MACHINE

The present invention relates to the field of brush holders and more particularly the brush holders for rotating electrical machines.

 A brush holder is a set of elements for holding or holding in place a brush of a rotating electric machine, for example a motor or a generator.

 A broom, usually based on graphite, ensures the transmission of electrical power between a movable element and a fixed element.

 The purpose of the brush holder device is to keep the brush in contact with the moving surface of the rotating electrical machine, for example a commutator or a ring, while exerting on this brush a certain pressure. Usually, the pressure is provided by means of an elastic device such as a spring.

 Dust is generated due to the friction of the blade against the movable member. These dusts are likely to lead to a degradation of the surface condition of the collector or ring and / or mechanical jamming and / or electrical insulation defects.

 WO 00/69049 discloses a dust suction system generated by a broom, comprising a collection device at the rear of the broom.

 There is a need for a more compact device.

The invention relates to a device for guiding a suction system, this suction system being intended to suck dust generated by a wiper blade on a rotating element of a rotating electrical machine, the guiding device being arranged to concentrate a flow of air, generated by the suction system, near the end of the blade in contact with the rotating member. The guiding device defines at least one suction chamber shaped to open towards the rotating element, this at least one chamber having a set of walls extending in the same longitudinal direction. This set of walls is shaped to surround a broom portion near this end in contact with the rotating member. This guiding device can thus be relatively compact and easy to install.

 This or these walls extending in the longitudinal direction will be said to be vertical in the present application.

 The vertical wall or walls surrounding the blade, over at least part of its height, the assembly formed by the blade and the guide device can occupy a relatively small volume. This set can therefore be set up in an installation more easily than the system of the document discussed above.

 The number of these vertical walls can be four, in particular for a broom general shape of pavement, but it goes without saying that one can provide one, two, three walls, five walls, or more. In particular, for a broom with a circular base, it would be advantageous to provide a guide device with a single circular wall, with an internal diameter slightly greater than the outer diameter of the base of the blade, in order to fit the brush best. For a hexagonal broom, it would be advantageous to provide a guiding device with a hexagonal section, in order to adjust best to the broom. In general, it is advantageous that the set of walls has a section corresponding to a slight enlargement of the base of the blade, in order to receive the blade while remaining relatively close to the blade.

 In the case of a set of four walls, each of these walls may advantageously be flat and perpendicular to the two walls which are adjacent to it, so that the section of the set of walls is substantially rectangular or even square. The set of walls can thus be adapted to generally shaped brushes paved.

 The walls can be flat and secured to each other with rounded or not. The walls may optionally be curved, and extend in the same direction, so as to form a cylinder.

 It will be understood that the suction chamber may be defined by an open volume on only one of its sides in order to better direct the suction flow.

By "a broom part near this end in contact with the rotating element", it will be understood that the ends of at least some of the vertical walls of the suction chamber remain above the end of the blade in contact with the rotating element, so that the guide device does not constitute an obstacle for the passage of the rotary element. Nevertheless, the guiding device surrounds a portion of the wiper close to the end of the wiper in contact with the rotary element, in particular enabling the surface of the wiper blade to be closely wrapped in contact with the rotary element and thus limiting any dust leak.

 Such a configuration can in particular make it possible to concentrate the airflow more efficiently and to limit the dispersion in the air of the dust generated by the friction between the blade and the movable element.

 By "close" it will be understood that the device will come close enough to the rotating element to limit the dispersion of dust, without coming into contact with the rotating element.

 According to a particular embodiment, the space between the guide device and the rotating element may be between 2 and 4 mm.

 Advantageously, the guiding device may comprise at least two vertical walls, one of which extends more than the other on the side of the opening towards the rotary element, so that when said guiding device is installed around the part of the blade in contact with the rotating element, one of these walls remains above the end of the blade in contact with the rotary element so as to let said rotating element when in rotation, and the another of these walls, called lateral, extends beyond, that is to say by convention below, the end of the blade in contact with the rotating element.

 This side wall or these two side walls may thus form a skirt to further concentrate the dust.

 For even more compactness, it can be provided that the suction chamber is centered around the brush.

 The vertical walls may be relatively close to the sides of the broom.

The end of the blade in contact with the rotating member may be only roughly planar. In particular, this end may have a shape substantially complementary to the shape of the rotary element, because of the wear due to friction. This end, intended to be rubbed against the rotating element, may be said horizontal in opposition to the vertical sides of the blade, intended to be surrounded by the chamber over part of their height. It will be understood that the friction end may form a non-straight angle with these so-called vertical sides: for example, it suffices for this purpose that the blade is brought into friction against a portion of the rotary member not perpendicular to the longitudinal direction of the blade , called vertical.

 More particularly, the guiding device may define two or more suction chambers. A plurality of suction chambers could make it possible to concentrate the suction flow more efficiently. For example, if the suction chamber is divided into two parts and each chamber is connected to a suction flow, then each chamber will have a more concentrated suction flow. This plurality of aspiration chambers may be delimited by the set of walls surrounding the broom over part of its height.

 Advantageously, the guiding device can be secured to a cage surrounding the blade.

 The fastening of the guide device on the broom cage can allow easier positioning of the guide device vis-à-vis the area to be sucked. In addition, the guide device can also be installed relatively easily on a door already in place.

 Advantageously, the guiding device can be made by overmolding around the cage.

 More particularly, the guiding device can be made in one piece with the cage. This device allows in particular to limit the number of parts and therefore the number of assembly operations during the installation of such a device on a rotating electrical machine.

Advantageously, the guiding device may comprise at least one connecting means to a conduit. More particularly, the connecting means ensures a tight connection between the guide device and the conduit. In particular, the connecting means may be an orifice passing through the guiding device in order to ensure the passage of the air flow from a suction chamber to a duct. The connecting means can also be coupled to a quilting at right angles. The connection can be provided by screwing or gluing, for example.

 According to another embodiment, the guiding device may be a device adapted to maintain the end of the duct near the brush portion in contact with the rotating element. For example, one could envisage a fixing lug, secured to the cage surrounding the broom. One could then consider a fixed end on the end of the conduit for example by screwing or gluing. The tip can then take various forms to distribute the suction flow, such as for example a wide tip, or other tips used with household vacuum cleaners.

 According to a particular arrangement, the guiding device may comprise at least one duct for connection to a suction unit.

 A suction unit is a device for generating an air intake flow. This suction group can be a suction group of the type used in clean rooms. We will not define further this device well known to those skilled in the art.

 More particularly, the suction chamber or chambers, the conduit, the connection and / or the tip may be made of an antistatic material or of any material covered with an antistatic coating.

 The use of an antistatic material prevents dust from adhering to the inner walls of these elements and thus limits the risk of clogging of the latter.

 According to a particular embodiment, the conduit is based on antistatic polyurethane.

 In particular, the guiding device may be made of an electrically insulating and heat-resistant material generated by the operation of the machine.

The use of an electrically insulating material prevents the formation of electric arcs, between the rotating element and the guiding device, which could generate operating disturbances of the machine, in particular by damaging the guiding device. The heat generated by the machine could melt a traditional plastic material and thus lose the dimensional stability of the guide device, necessary stability due to the proximity of the guide device and the rotating member.

 The material used is advantageously an acetal resin, non-conductive and having a temperature range of use ranging from -40 ° C to more than 110 ° C.

 It is also proposed a dust suction system comprising a suction unit and at least one guiding device as described above.

 In particular, the suction unit may be able to generate an optimum flow to suck the dust.

 It will be understood that a suction flow rate that is too low can result in the loss of all or part of the dust and make the guiding device ineffective. Conversely, too much flow can lead to unnecessary energy expenditure.

Advantageously, it has been determined empirically that the suction flow inside the guiding device could advantageously take values ranging from 10 to 20 m ³ / h, with a speed of 15 m / s to 40 m / h. s and preferably equal to 20 m / s.

 It will be readily understood that the suction flow generated by the suction unit is a function of various parameters including the number of brushes, the dimensions of the guiding device, the desired level of cleanliness, etc.

 More particularly, the suction system may comprise a nanny, a suction unit and several guiding devices as described above, the nanny ensuring the junction and the distribution of the air flow between the suction unit and the devices. guidance. The nanny divides the suction flow generated by the suction unit and can distribute the flow unevenly, especially depending on the length and diameter of the ducts.

The invention furthermore relates to a device for guiding a suction system, this suction system being intended to suck dust generated by a rubbing broom on a rotating element of a rotary electrical machine, the guiding device being arranged to concentrate a flow of air, generated by the suction system, near the end of the blade in contact with the rotating element. The guiding device defines at least one suction chamber shaped to open towards the rotary member, and surround a brush portion near this end in contact with the rotating member. The suction chamber may advantageously be centered around the broom.

 The invention is now described, with reference to the non-limiting drawings, in which:

 Figure 1 is an overall perspective view of a guide device integrated on a brush holder of a rotating electrical machine according to one embodiment of the invention.

 FIG. 2 is a perspective bottom view of an example of a guiding device according to the embodiment of FIG. 1.

 A particular embodiment of the invention is shown in these figures. In particular, the guide device according to the example shown is in the form of a soleplate 10.

 This sole 10 is shown in plan view in the form of a square parallelepiped having at its center an orifice 13. This orifice 13 is intended to allow a cage 3 to pass to hold a brush 1. According to a variant not shown, the orifice 13 can be directly adapted to directly hold the broom 1.

 The orifice 13 has in particular a polarizer 13 'making it possible to avoid errors in mounting the blade 1 on the guiding device

10.

 In the example shown, the orifice 13 is surrounded by a suction chamber 12 open towards the rotary element 2. This suction chamber 12 comprises two orifices 14 passing through the soleplate 10 in order to ensure the flow of the flow. air F from chamber 12 to the ducts

4. The joining of the conduits 4 on the sole is in particular ensured by an angular tapping 14 ', glued in each orifice 14.

The quilts at right angle 14 'are traditional devices well known to those skilled in the art. They can for example be made of metal or plastic. The suction chamber 12 is delimited by four vertical walls surrounding a portion of the blade 1, including two side walls, opposite to one another, which extend towards the rotary member 2 more than the other two vertical walls. , so as to form a skirt. It is preferable that these two other vertical walls do not constitute an obstacle to the passage of the rotary element.

 The suction chamber 12 is centered around the broom 1.

 The materials used for the soleplate 10, the connecting means 14 'or the conduit 4 withstand a temperature ranging from 60 ° C to 200 ° C and preferably at least 80 ° C.

 The materials used are also antistatic or treated in such a way that they do not retain dust in order to limit the accumulation of dust at the level of the various elements and therefore the problems of mechanical operation.

 According to a particular embodiment, the soleplate 10 is polyacetal. One could also consider making polyphenylene sulfone, polycarbonate or polyamide, subject to meet the specificities below:

 Tensile strength ranging from 60 MPa to 200 MPa, advantageously at least 70 MPa;

 - Continuous use temperature ranging from 60 ° C to 300 ° C, preferably at least greater than 1 10 ° C;

- Electrical resistance ranging from 1.10 ¹⁰ Ohm / cm to 1.10 ²⁰ Ohm / cm, preferably 1.10 ¹⁵ Ohm / cm.

 The sole 10 also has insulating characteristics, making it possible to approach closer to the rotating element 2, without generating the formation of electric arcs, between the rotating element 2 and the sole 10, which could damage the sole 10 or the rotating element 2 and thus generate operating disturbances of the machine. In the example, the soleplate 10 is made of acetal resin by overmolding or bonding around the cage 3.

The guiding device is adapted to integrate into a suction system comprising in particular a suction group, it being understood that this apiration group generates a flow sufficient to suck continuously most of the dust generated by the friction between the blade and the rotating element, preferably at least 80%.

 In the example shown, the sole 10 has the following external dimensions 50mm x 50mm, for a height ranging from 10 to

20 mm. This sole is intended to surround a traditional broom having the following dimensions: 32mm x 32mm x Y mm, the height Y being a variable element depending on the wear of the blade 1. For the dimensions mentioned, an aspiration flow F to the inside of the sole 10 of 15m / s can suck about 80% of the dust generated.

 The suction system may for example be adapted to a generator comprising twelve corresponding brushes and brush holders, each comprising a sole as described above. To ensure an identical distribution of the suction flow between each sole, is inserted between the suction unit and each sole a nurse capable of distributing the flow. To illustrate the example above, we could detail the system of apiration in the following way:

An apiration group capable of generating a primary flow of at least 120 m ³ / s,

 - A nurse capable of dividing the primary flow in at least as much secondary flow as ducts to connect the soles, that is to say in our example at least twelve outputs;

 - One sole per brush holder;

 - Ducts, adapted to convey the dust without loss of flow, ensuring the connection between the apiration group, the nurse and soles.

 In order to obtain a better distribution of the flow F inside the soleplate, it may be envisaged to connect each chamber to two ducts. The nanny then understands twice as many exits as soles.

Claims

1. A device for guiding (10) a suction system, said suction system being intended to suck dust generated by a wiper (1) rubbing on a rotary member (2) of a rotating electrical machine, the guiding device (10) being arranged to concentrate a flow of air (F), generated by the suction system, close to the brush end (1) in contact with the rotating element (2 ), the guiding device defining at least one suction chamber (12) shaped to open towards the rotating element, said at least one chamber having a set of walls extending in a longitudinal direction, said assembly being shaped to surround a broom portion near said end. 2. guiding device (10) according to claim 1, characterized in that it is secured to a cage (3) surrounding the blade (1) · 3. Guiding device (10) according to claim 2, characterized in that it is made in one piece with the cage (3). 4. Guiding device (10) according to any one of claims 1 to 3, characterized in that it comprises at least one connecting means (14) to a conduit (4). 5. Guiding device (10) according to any one of claims 1 to 4, characterized in that it comprises at least one duct (4) for connection to a suction unit. 6. Guiding device (10) according to any one of claims 1 to 5, characterized in that the suction chamber (12), the connecting means (14) and / or the duct (4) are made of an antistatic material or covered with an antistatic coating. 7. Guiding device (10) according to any one of claims 1 to 6, characterized in that the guide device (10) is made of an electrically insulating material and heat resistant generated by the operation of the machine. 8. Guiding device according to one of claims 1 to 7, characterized in that the guide device defines a plurality of suction chambers. 9. Guide device (10) according to one of claims 1 to 8, characterized in that among the walls of the suction chamber (12), at least one wall extends further from the side of the opening towards the rotary member at least one other of said walls, so that when said guide device is installed around the portion of the blade (1) in contact with the rotary member (2), one of said walls remains at above the end of the blade in contact with the rotary member so as to pass said rotary member, and the other of said walls extends below the end of the blade in contact with the rotary member. 10. Guiding device according to one of claims 1 to 9, wherein the set of walls comprises four flat walls secured to each other, each of said walls being perpendicular to the adjacent walls. 1. A dust suction system comprising a suction unit and at least one guiding device (10) according to any one of claims 1 to 10. 12. Suction system according to claim 1 1, characterized in that it comprises a nurse, a suction unit and several guiding devices (10), the nurse ensuring the junction and the distribution of the air flow ( F) between the suction unit and the guiding devices (10).